diff --git a/cms/envs/common.py b/cms/envs/common.py
index 1f95f37d6b..4794155453 100644
--- a/cms/envs/common.py
+++ b/cms/envs/common.py
@@ -2322,3 +2322,17 @@ LOGO_URL_PNG = None
 LOGO_TRADEMARK_URL = None
 FAVICON_URL = None
 DEFAULT_EMAIL_LOGO_URL = 'https://edx-cdn.org/v3/default/logo.png'
+
+# .. toggle_name: ERROR_ON_DEPRECATED_EDX_PLATFORM_IMPORTS
+# .. toggle_implementation: DjangoSetting
+# .. toggle_default: False
+# .. toggle_use_cases: rollout
+# .. toggle_creation_date: 2021-01-20
+# .. toggle_target_removal_date: 2021-01-27
+# .. toggle_tickets: https://github.com/edx/edx-platform/pull/25932
+# .. toggle_description: Whether to raise an exception where,
+#  normally, a DeprecatedEdxPlatformImportWarning would be raised.
+#  This will allow us to test dropping support for the deprecated
+#  import paths without yet removing all of the import_shims
+#  machinery.
+ERROR_ON_DEPRECATED_EDX_PLATFORM_IMPORTS = False
diff --git a/cms/envs/devstack.py b/cms/envs/devstack.py
index 7969d335b7..cf538ec1a7 100644
--- a/cms/envs/devstack.py
+++ b/cms/envs/devstack.py
@@ -240,3 +240,6 @@ CORS_ALLOW_HEADERS = corsheaders_default_headers + (
 ################### Special Exams (Proctoring) and Prereqs ###################
 FEATURES['ENABLE_SPECIAL_EXAMS'] = True
 FEATURES['ENABLE_PREREQUISITE_COURSES'] = True
+
+# Don't tolerate deprecated edx-platform import usage in devstack.
+ERROR_ON_DEPRECATED_EDX_PLATFORM_IMPORTS = True
diff --git a/cms/envs/test.py b/cms/envs/test.py
index c854f19ad8..5cc0f0f005 100644
--- a/cms/envs/test.py
+++ b/cms/envs/test.py
@@ -326,3 +326,6 @@ LOGISTRATION_RATELIMIT_RATE = '5/5m'
 LOGISTRATION_API_RATELIMIT = '5/m'
 
 REGISTRATION_VALIDATION_RATELIMIT = '5/minute'
+
+# Don't tolerate deprecated edx-platform import usage in tests.
+ERROR_ON_DEPRECATED_EDX_PLATFORM_IMPORTS = True
diff --git a/import_shims/warn.py b/import_shims/warn.py
index 97e8177cd6..598cda95a8 100644
--- a/import_shims/warn.py
+++ b/import_shims/warn.py
@@ -7,6 +7,7 @@ See /docs/decisions/0007-sys-path-modification-removal.rst for details.
 
 import warnings
 
+from django.conf import settings
 from edx_django_utils.monitoring import set_custom_attribute
 
 
@@ -37,10 +38,30 @@ class DeprecatedEdxPlatformImportWarning(DeprecationWarning):
         ).format(self=self)
 
 
+class DeprecatedEdxPlatformImportError(Exception):
+    """
+    Error: An edx-platform module is being imported from an unsupported location.
+
+    See `DeprecatedEdxPlatformImportWarning` above for context.
+    """
+
+    def __init__(self, old_import, new_import):
+        super().__init__()
+        self.old_import = old_import
+        self.new_import = new_import
+
+    def __str__(self):
+        return (
+            "Importing {self.old_import} instead of {self.new_import} is deprecated"
+        ).format(self=self)
+
+
 def warn_deprecated_import(old_import, new_import):
     """
     Warn that a module is being imported from its old location.
     """
+    if settings.ERROR_ON_DEPRECATED_EDX_PLATFORM_IMPORTS:
+        raise DeprecatedEdxPlatformImportError(old_import, new_import)
     set_custom_attribute("deprecated_edx_platform_import", old_import)
     warnings.warn(
         DeprecatedEdxPlatformImportWarning(old_import, new_import),
diff --git a/lms/envs/common.py b/lms/envs/common.py
index 90b2c457f0..cac27c859e 100644
--- a/lms/envs/common.py
+++ b/lms/envs/common.py
@@ -4179,3 +4179,17 @@ LOGO_URL_PNG = None
 LOGO_TRADEMARK_URL = None
 FAVICON_URL = None
 DEFAULT_EMAIL_LOGO_URL = 'https://edx-cdn.org/v3/default/logo.png'
+
+# .. toggle_name: ERROR_ON_DEPRECATED_EDX_PLATFORM_IMPORTS
+# .. toggle_implementation: DjangoSetting
+# .. toggle_default: False
+# .. toggle_use_cases: rollout
+# .. toggle_creation_date: 2021-01-20
+# .. toggle_target_removal_date: 2021-01-27
+# .. toggle_tickets: https://github.com/edx/edx-platform/pull/25932
+# .. toggle_description: Whether to raise an exception where,
+#  normally, a DeprecatedEdxPlatformImportWarning would be raised.
+#  This will allow us to test dropping support for the deprecated
+#  import paths without yet removing all of the import_shims
+#  machinery.
+ERROR_ON_DEPRECATED_EDX_PLATFORM_IMPORTS = False
diff --git a/lms/envs/devstack.py b/lms/envs/devstack.py
index a0f4907cd1..943d76ff0e 100644
--- a/lms/envs/devstack.py
+++ b/lms/envs/devstack.py
@@ -431,3 +431,6 @@ if os.path.isfile(join(dirname(abspath(__file__)), 'private.py')):
 ################### Special Exams (Proctoring) and Prereqs ###################
 FEATURES['ENABLE_SPECIAL_EXAMS'] = True
 FEATURES['ENABLE_PREREQUISITE_COURSES'] = True
+
+# Don't tolerate deprecated edx-platform import usage in devstack.
+ERROR_ON_DEPRECATED_EDX_PLATFORM_IMPORTS = True
diff --git a/lms/envs/test.py b/lms/envs/test.py
index 3f26b8dee2..c22875dc02 100644
--- a/lms/envs/test.py
+++ b/lms/envs/test.py
@@ -588,3 +588,6 @@ LOGISTRATION_RATELIMIT_RATE = '5/5m'
 LOGISTRATION_API_RATELIMIT = '5/m'
 
 REGISTRATION_VALIDATION_RATELIMIT = '5/minute'
+
+# Don't tolerate deprecated edx-platform import usage in tests.
+ERROR_ON_DEPRECATED_EDX_PLATFORM_IMPORTS = True
diff --git a/openedx/tests/settings.py b/openedx/tests/settings.py
index 5e92e3c58c..fd4f3469cc 100644
--- a/openedx/tests/settings.py
+++ b/openedx/tests/settings.py
@@ -133,3 +133,6 @@ RUN_BLOCKSTORE_TESTS = False
 SOFTWARE_SECURE_REQUEST_RETRY_DELAY = 60 * 60
 # Maximum of 6 retries before giving up.
 SOFTWARE_SECURE_RETRY_MAX_ATTEMPTS = 6
+
+# Don't tolerate deprecated edx-platform import usage in tests.
+ERROR_ON_DEPRECATED_EDX_PLATFORM_IMPORTS = True